Yamaha YSR50

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Yamaha YSR50
Production 87-93
49.3cc 2-stroke, single cylinder, air-cooled with reed valve
Bore / Stroke 40.0mm x 39.2mm
Compression ratio 7.4:1
Top Speed 38 mph
Horsepower 7 horsepower @ 8,800 RPM
Torque 0.59 kg-m @ 8,500 RPM
Fuel System Carburetor, Mikuni VM16SH
Spark Plug NGK B8HS '87-93
Battery YUASA 6N4-2A-2 '87-93
Transmission 5-speed constant mesh
Final Drive Chain: 420x100
Front Sprocket 12T
Rear Sprocket 44T
Front Tire 3.50-12 '87-93
Rear Tire 4.00-12 '87-93
Wheelbase 1050mm
Length 1575mm
Width 635mm
Height 930mm
Seat Height 650mm
Weight 75kg (dry),
Recommended Oil Yamalube 10w-40
Related Yamaha RX50 (contained same engine), Yamaha YSR80
Competition Honda NSR50, Aprilia RS50
Manuals Service Manual

Brochures ·

The Yamaha YSR50 is a motorcycle produced by Yamaha from 1987 to 1993.

This style of miniature motorcycle is known as a pocket bike. Although small in size, these machines are capable of giving surprising performances in the hands of skilled operators. Enthusiast groups organize races and endurance runs for pocket-bikes, of which the YSR Yamaha is the most popular. It mainly competes with the likes of the Honda NSR50. The limited edition Yamaha RX50 shared the same engine.

History[edit | edit source]

Yamaha YSR 50 and YSR 80 sport models goes on sale in Japan in 1986, and had the look of a re-shaped, scaled-down YZR500 factory racer that appealed to the spirit of race enthusiasts. The 2-stroke single-cylinder engine had a maximum output of 7 ps for the 50cc and 8.8 ps for the 80cc, a return type 5-speed transmission, front disc brake and other features to offer full-fledged sport riding potential. It became a standard in the mini-bike races popular at the time. 1992 was the last year of production, and the price was 189.000 yen for the 50cc and 211.000 yen for the 80cc.

1987[edit | edit source]

1990[edit | edit source]

1991[edit | edit source]

1992[edit | edit source]

1992 Yamaha YSR50